Created August 21, 1876, from Bexar County. Named for a native of New Jersey, Robert Cochran, a private who died for Texas Independence in the siege of the Alamo.
Indian hostilities and the distance to market and supplies made settlement slow. The 1900 census listed 25 cowboys. In 1910 there were 75 persons; then 67 in 1920.
Organized May 6, 1924, with Morton as county seat. Oil discovery and development of irrigation caused rapid growth, and made it a farm and petroleum center.
Site of Silver Lake, a saline lake known to early Spanish explorers as Laguna Quemado.